scholarly journals A 3D numerical analysis of the compaction effects on the behavior of panel-type MSE walls

2020 ◽  
Vol 12 (1) ◽  
pp. 1704-1724
Author(s):  
Myoung-Soo Won ◽  
Christine P. Langcuyan
Keyword(s):  
Tensile Deformation ◽  
Lateral Displacement ◽  
Tensile Force ◽  
Soil Reinforcement ◽  
Load Application ◽  
Great Resistance ◽  
Mse Wall ◽  
Reinforcement Material ◽  
Mse Walls ◽  
Surcharge Load

AbstractSoil is weak in tension but strong in compression. The resistance to tensile deformation of soil is given by the tensile force of the reinforcement in the reinforced soil, and the tensile force of the reinforcement is generated by the frictional force at the soil-reinforcement interface. When the soil-reinforcement is effectively interacted by the compaction, the deformation of the soil becomes equal to the tensile deformation of the reinforcement material, which means that the soil is bound to the tensile force of the reinforcement material and thus has a great resistance to the tensile deformation. Therefore, compaction is one of the major parameters affecting the behavior of the mechanically stabilized earth (MSE) wall. In this study, a series of numerical analyses was performed to investigate the compaction effect on the behavior of the MSE walls. The results showed that the horizontal displacement of the MSE wall significantly increased during the construction and decreased because of surcharge load application after the construction. In addition, the strains of reinforcement increased significantly during the construction and decreased slightly because of surcharge load application after the construction. Therefore, it is important to consider the compaction loads when modeling the MSE walls, so that the lateral displacement at wall facing will not be underestimated during construction and will not be overestimated because of surcharge load application after the construction.

Influence of Inadequate Compaction near Facing on Construction Response of Wrapped-Face Mechanically Stabilized Earth Walls

2008 ◽  
Vol 2045 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Kianoosh Hatami ◽  
Alan F. Witthoeft ◽  
Lindsay M. Jenkins
Keyword(s):  
Structural Damage ◽  
Lateral Displacement ◽  
Friction Angle ◽  
Mechanically Stabilized Earth ◽  
Mechanically Stabilized Earth Walls ◽  
Heavy Equipment ◽  
Mse Wall ◽  
Mse Walls ◽  
Wall Models ◽  
Mechanically Stabilized

Standard practice for the compaction of backfill soil near the facing of a mechanically stabilized earth (MSE) wall or embankment is to use lightweight compaction equipment to prevent excessive facing deformation. Complications caused by compaction with heavy equipment near the facing could also include misalignment or structural damage of the wall facing and overstressing of the reinforcement layers. However, inadequate compaction near the facing could result in later settlement or appearance of voids behind the facing. Little research has been reported in the literature to quantify the effects of loosely compacted soil behind the facing on the stability and serviceability of MSE walls at the end of construction. The influence of inadequate compaction effort near the facing on the construction performance of idealized wrapped-face MSE wall models was investigated by using a numerical simulation approach. It was shown that inadequate backfill compaction within 1 m of the wall facing could increase the wall lateral displacement by about 40% and the reinforcement strains by about 90% compared with the response of an otherwise identical (i.e., control) wall model constructed with uniform compaction throughout the backfill. This effect was found to be more significant for higher-quality backfills with greater friction angle values and less stiff reinforcement materials. Results of this study on idealized wrapped-face wall models highlight the importance of proper soil compaction and quality control near the facing of MSE walls and offer example quantitative increases that could be expected in the out-of-alignment and reinforcement loads in these MSE structures.

Study on the Lateral Displacement of Super-Long Pile under a Asymmetrical Surcharge Load in Soft Clay

2014 ◽  
Vol 580-583 ◽  
pp. 733-737
Author(s):  
Qi Li ◽  
Xiao Li Lu
Keyword(s):  
Lateral Displacement ◽  
Soft Soil ◽  
Soft Clay ◽  
Three Dimensional ◽  
Influence Factors ◽  
Major Influence ◽  
Small Contribution ◽  
Practical Engineering ◽  
Surcharge Load ◽  
Building Load

The pile will have a large lateral displacement in soft soil under the role of heaped load. Based on Biot consolidation theory, combined with a certain highway project, a three-dimensional FEM model is established, the process that the soil lateral deformation under heaped load lead to the pile side displacement was simulated. On the ground of the former result, the influence factors for the displacement of pile top and the pile displacement field distribution are analysed. The results show that, the building load area, load grade and the distance from loading area to pile have a major influence on the pile side displacement. On the other hand, the load on pile top have a very small contribution for stability of anti side displacement. The buildings nearby the area of pile foundation should be given attention in practical engineering.

scholarly journals Mechanically Stabilized Earth with Steel Reinforcement

2021 ◽  
Vol 9 (3) ◽  
pp. 135-141
Author(s):  
Magdi M. E. Zumrawi ◽  
Abubaker B. B. Barakat ◽  
Idris M. I. Abdalla ◽  
Rabab A. A. Altayeb
Keyword(s):  
Retaining Wall ◽  
Soil Reinforcement ◽  
Current Status ◽  
Mechanically Stabilized Earth ◽  
Steel Strips ◽  
Wall Structures ◽  
Backfill Soil ◽  
Mse Walls ◽  
Mechanically Stabilized

This paper presents the Mechanically Stabilized Earth (MSE) technique as a practical option for earth retaining wall structures. The literature pertaining soil reinforcement methods and their application in MSE walls were intensively reviewed. The present work focused on evaluating the performance of MSE walls with backfill soil reinforced by steel strips. Almolid square overpass bridge in Khartoum, which was constructed in 2015 with MSE walls as lateral support of the overpass ramps, was considered as case study. Based on field observations, the current status of the overpass bridge has proven that the use of MSE walls is successful and beneficial for sustainability of the overpass.  

Two-phase tension of a carbon nanotube

2020 ◽  
Vol 05 (01) ◽  
pp. 2050001
Author(s):  
Iman Evazzade ◽  
Ivan Lobzenko ◽  
Oleg Golubev ◽  
Elena Korznikova
Keyword(s):  
Carbon Nanotube ◽  
Domain Walls ◽  
Tensile Deformation ◽  
Tensile Force ◽  
Physical And Mechanical Properties ◽  
Phase Region ◽  
Polymer Chains ◽  
Dynamics Simulation ◽  
Two Phase ◽  
Tensile Forces

Heterostructures consisting of new two-dimensional nanomaterials may possess non-trivial physical and mechanical properties, promising for many applications. It is interesting that in some cases it is possible to create heterostructures simultaneously consisting of weakly and strongly stretched domains having the same chemical composition, as have been witnessed earlier for some polymer chains, DNA, and intermetallic nanofibres that demonstrate the effect of two-phase stretching. These materials with relatively large tensile forces tend to split into domains with less and greater tensile deformation. Within the two-phase region of deformation, the average deformation of the sample increases with a constant tensile force, with the growth of a domain with a higher strain due to a domain with a lower strain. In this paper, the two-phase stretching of carbon nanotubes has been studied by means of molecular dynamics simulation. It has been established that the load-deflection curves during axial tension exhibit hysteresis-like behavior due to energy dissipation during nucleation and motion of domain walls. It is shown that in the two-phase tension regime, a carbon nanotube is a special case of a heterostructure, the properties of which can be controlled by changing the size of the domains of each phase by applying elastic deformation.

In situ shear tests of soil blocks with roots

1998 ◽  
Vol 35 (4) ◽  
pp. 579-590 ◽  
Author(s):  
Tien H Wu ◽  
Alex Watson
Keyword(s):  
Shear Strength ◽  
Root System ◽  
Tensile Force ◽  
Failure Surface ◽  
Soil Reinforcement ◽  
Shear Tests ◽  
Maximum Displacement ◽  
Shearing Resistance ◽  
Simplified Procedures

In situ shear tests were performed on soil blocks that contained roots to study the contribution of roots to the shear strength in a case where the shear deformation is not constrained to a thin zone. The shearing resistance of the soil-root system, the tensile force in selected roots, and the deformation of the soil block were measured. The roots were exposed after the test and their positions were determined and used to estimate the initial positions. The root force and the shearing resistance of the soil-root system were estimated with known solutions and compared with measured root force and shearing resistance. None of the roots that passed through the shear zone failed in tension at the maximum displacement. As a consequence, the root resistance is much less than that found in a case where the failure surface is restricted to the boundary between a weak soil and a firm base and where roots are anchored in the firm base and fail in tension. Simplified procedures for estimating root forces are suggested for the case of a thick shear zone.Key words: in situ test, roots, shear strength, slope stability, soil reinforcement, soil–root interaction.

scholarly journals Discrete Element Analysis of the Strength Anisotropy of Fiber-Reinforced Sands Subjected to Direct Shear Load

2020 ◽  
Vol 10 (11) ◽  
pp. 3693
Author(s):  
Linxian Gong ◽  
Lei Nie ◽  
Yan Xu
Keyword(s):  
Fiber Orientation ◽  
Tensile Force ◽  
Orientation Angle ◽  
Discrete Element ◽  
Soil Reinforcement ◽  
Direct Shear ◽  
Strength Anisotropy ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Fiber Orientation Angle

Soil reinforcement with natural or synthetic fibers enhances its mechanical behavior in various applications. Fiber-reinforced sands (FRS) can be relatively anisotropic because of the fiber self-weight and the compaction technique. However, the microscopic mechanisms underlying the anisotropy are still poorly understood. This study used a discrete element approach to analyze the microscopic mechanisms underlying the strength anisotropy of FRS due to fiber orientation. Analysis of contact networks revealed that the optimum fiber orientation angle is perpendicular to the main direction of strong contact force in direct shear testing. These fibers produced the largest increase in shear zone thickness, normal force around the fiber body, effective contact area, tensile force along fibers, and energy storage/dissipation. This study is valuable for further understanding of the mechanical behaviors of FRS.

scholarly journals STUDI PARAMETRIK JARAK PENGARUH PENURUNAN DAN PERGERAKAN LATERAL AKIBAT VACUUM PRE-LOADING PADA DAMAGE AREA SEKITAR

2020 ◽  
Vol 3 (4) ◽  
pp. 1091
Author(s):  
Mario Oktavianus Lay ◽  
Inda Sumarli ◽  
Ali Iskandar
Keyword(s):  
Lateral Displacement ◽  
Distance Effect ◽  
Soil Improvement ◽  
Deformation Analysis ◽  
Finite Element Program ◽  
Damage Area ◽  
Dimensional Finite Element ◽  
Element Program ◽  
Surcharge Load ◽  
New Material

 ABSTRACTSoil-fill is type of soil with low bearing capacity, therefore it’s need soil improvement to resolve the settlement. Soil improvement divided into 2 categories, namely methods that use new material and reinforcement. Commonly used method is PVD combined with vacuum pre-loading. Pre-loading is an application to increase surcharge load which aims to reduce the primary settlement occurs. Pre-loading not only causes settlement, but also cause lateral displacement which cause damage to the outside area around the improvement area. Thus, an analysis of distance effect between the improvement boundary and outside of improvement area in needed to prevent damage to utility around the site. Deformation analysis will be assisted by 2-Dimensional finite element program. Width of the improvement area is 80 meters with a depth of PVD is 14.5 meters to verify parameters. With the parameters that have been verified, an analysis is carried out on PVD with depth of 5m to 30m to determined distance effect of settlement and lateral displacement from boundary of the improvement area to until the value of the settlement and lateral displacement reaches <2cm. Result of studies on general is to find distance effect caused by vacuum pre-loading in areas outside the improvement boundary.ABSTRAKTanah hasil urugan merupakan jenis tanah lunak dengan daya dukung yang rendah, sehingga terjadi penurunan konsolidasi dan membutuhkan perbaikan. Perbaikan tanah dibagi menjadi 2 kategori, yaitu metode yang menggunakan material baru dan menggunakan pemanfaatan perkuatan. Metode yang umum digunakan adalah PVD yang dikombinasikan dengan vacuum pre-loading. Pre-loading adalah aplikasi penambahan beban surcharge yang bertujuan agar terjadinya penurunan primer. Pre-loading tidak hanya menyebabkan penurunan, tetapi juga menyebabkan terjadinya perpindahan secara lateral kearah luar yang dapat menyebabkan kerusakan pada area luar disekitar daerah perbaikan. Sehingga, dibutuhkan analisis jarak pengaruh antara batas lahan perbaikan dengan daerah luar perbaikan, untuk mencegah kerusakan pada struktur atau utilitas disekitar lokasi perbaiki. Analisis deformasi menggunakan program elemen hingga 2D. Lebar area perbaikan 80 meter dengan kedalaman PVD 14.5 meter untuk melakukan verifikasi parameter. Dengan parameter yang telah diverifikasi, dilakukan analisis pada PVD dengan kedalaman 5m hingga 30m untuk mengetahui jarak pengaruh penurunan dan pergerakan lateral dari batas lahan perbaikan hingga nilai penurunan dan pergerakan lateral <2 cm. Hasil studi secara umum menunjukkan seberapa besar jarak pengaruh yang diakibatkan oleh vacuum pre-loading pada daerah diluar batas perbaikan.

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